Styrene copolymers combined with metallic species in deposition inhibition

ABSTRACT

Provided herein are compositions useful for inhibiting the formation of gummy residues on equipment in processing operations which liberate tiny adhesive particles having a tendency to agglomerate into larger particles and/or films. The compositions comprise a complex or adduct formed from styrene/methacrylic acid copolymer and calcium ions. The compositions according to the invention may be added to a processing system at any point, either upstream or downstream from the location at which residues are formed. Compositions according to the invention may be applied by spray techniques.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This Application is a continuation-in-part of U.S. applicationSer. No. 09/776,985 which was filed on Feb. 5, 2001 and is currentlystill pending, the entire contents of which are herein incorporated byreference thereto.

TECHNICAL FIELD

[0002] This invention relates to compositions of matter useful incausing tacky surfaces or materials to be rendered less tacky. Moreparticularly, the invention relates to compositions useful in preventingcoagulation in solutions comprising minute particles of tacky materials.The compositions and processes detailed herein are especiallywell-suited for use in paper mills and other employments where solutionscontaining sticky particles come into contact with process equipment andhave the propensity to cause fouling of the surfaces of such equipmentby agglomeration of such particles.

BACKGROUND

[0003] The formation of troublesome agglomerations of sticky bodies inaqueous solutions used in processing various chemical materials has beenobserved in various systems for some time. Such formation is aparticular noteworthy problem in the paper and pulp manufacturingindustry, regardless of the method used to pulp raw wood.

[0004] In general terms, there are two methods which are recognized bythose in the paper science arts for making a pulp from which many usefulproducts may be derived. The qualities of the pulp produced by eachprocess renders them each useful in particular end-use applications.

[0005] The first of such processes is a chemical process, which is knownas the “Krafft” process, and involves chemically treating wood chips andthe like at an elevated temperature with a strongly alkaline aqueoussolution of sodium sulfide in order to produce a pulp having most of thelignins and resins removed from the interstices between the individualfibers.

[0006] The second of such processes is known as mechanical pulping andentails forcing de-barked logs against a grinding stone or metal diskscalled “refiners” in order to produce a pulp. From the mechanicalprocess is produced a pulp product having more of the lignins and theresins remaining in the pulp than in the Krafft process. There are otherprocesses employed for pulping, which contain some character of each ofthe chemical and the mechanical processes. In one variant, wood chipsare treated with steam in the presence of caustic soda for a prescribedtime prior to being subject to grinding in the mechanical process. Inanother variant, wood chips are impregnated with sulfur compounds priorto the steaming.

[0007] Regardless of the method used to produce a pulp, all pulpingprocesses are carried out in the presence of water, which is capable ofacting as a carrier for all of the materials present during the pulping.Some of the materials include as aforesaid, the resins and lignins,which are capable of existing in the form of soaps. One particularlytroublesome property of these materials is that while soluble at high pHlevels, they tend to exist in the form of particulate precipitates inthe presence of divalent metal ions, such as the alkaline earth metals.The nature of these particulate precipitates is that they are generallyvery sticky on their exterior and thus have a propensity towardsformation of larger gummy globules and/or films on equipment with whichthey come into contact. This problem is typically manifest at the pointat which the soluble resin and lignin first come into contact with asource of di-valent metal cation, which in the case of the chemicalprocess is usually in the first washer which the pulp encounters afterleaving the digesters because this is where fresh rinse water containingdi-valent metal ions enters such a chemical pulping system. The initialdeposition of such particles is often in the form of a rough film. Asdeposition continues, thick incrustations form, particularly on exposededges to such an extent as to interfere with the operation of the pulpmill equipment. Eventually, portions of, or even the whole operationmust be shut down to enable cleaning of the machinery, which is a costlyand time-consuming endeavor.

[0008] Another class of materials known as “stickies” are troublesome inpulping and like operations. Whereas pitch, resin, and the like arisesfrom the processing of virgin pulp, stickies arise from secondaryfibers. Stickies are described in U.S. Pat. No. 4,956,051 which isincorporated in its entirety herein by reference thereto.

[0009] The prior art is replete with the attempts of various workers toprolong or even eliminate the formation of such deposits on paper millequipment. For example, U.S. Pat. No. 3,992,249 which is incorporatedherein in its entirety by reference thereto, teaches a process forinhibiting the deposition of adhesive pitch particles onto the surfaceof pulp-making equipment, prior to beating, from the water with which acellulose fiber suspension having a content of the particles is beingwashed. The process comprises washing the suspension in a pulp washercontaining an aqueous solution of an anionic polymer containing at leastabout 25 mol percent, but not more than about 85 mol percent, ofhydrophobic-oleophilic linkages. Hydrophobic oleophilic linkagessuitable for this employment are selected from the group comprisingstyrene, isobutylene, methylstyrene, allyl stearate, octadecyl acrylate,octadecene, dodecene, n-octadecylacrylamide, vinyl stearate and vinyldodecyl ether. Also present in the solution is at least about 15 molpercent, but not more than about 75 mol percent, of hydrophilic acidlinkages. Hydrophilic acid linkages suitable for this use are selectedfrom the group comprising acrylic acid, methacrylic acid, maleic acid,itaconic acid, acrylamidoacetic acid, maleamic acid and styrenesulfonicacid. A pitch-polymer complex of the particles and the polymer is formedby their admixture, which is removed with the water used to wash thecellulose fiber suspension. Thus, substantially all of the pitch-polymercomplex is separated from the cellulose fiber suspension. The amount ofthe polymer used is in the range of about 0.5 to 100 parts by weight permillion parts by weight of the suspension.

[0010] U.S. Pat. No. 4,184,912 which is incorporated herein in itsentirety by reference thereto, teaches a method of inhibiting pitchformation in paper mill pulp systems which comprises adding to suchsystems, at a point prior to where pitch deposits normally occur, atleast 0.5 ppm, based on the weight of the pulp, of a compositioncomprising varying amounts of surfactants. One such system containsvaried amounts of: Non-ionic surfactant; Anionic Dispersant; AnionicPolymer having molecular weight less than 100,000. In anotherembodiment, the surfactants comprise: an ethoxylated phenol; analkyl-substituted naphthalene sulfonate; and an acrylic acid co-polymer(molecular weight between 5,000 and 40,000).

[0011] U.S. Pat. No. 6,143,800 which is incorporated herein in itsentirety by reference thereto, discloses compositions and methods forinhibiting deposition of organic contaminants in equipment associatedwith a pulping operation which entails the addition of a compositioncomprising: a dinonyl sulfosuccinate anionic surfactant; and amultivalent cation to the system wherein the weight ratio of saiddinonyl sulfosuccinate anionic surfactant to multivalent cation rangesfrom about 1:4 to about 1:100. A composition embraced by theabove-mentioned description is added to the pulp or the surfaces ofpulping mill machinery in an effective deposition inhibiting amount.

[0012] However, each of the methods of the prior art has its owndrawbacks. For example, the teachings of U.S. Pat. No. 3,992,249 usescalcium to form pitch and subsequently adds a sodium salt copolymer toprevent further deposition of unwanted solids such as pitch, stickies,and the like. U.S. Pat. No. 4,184,912 and 6,143,800 claim the use ofsurfactants to control the deposition of stickies, pitch, and the like,but when the fiber slurry is diluted with white water from thepaper-making machinery the surfactants tend to de-sorb from the surfacesof the stickies, pitch, and like particles. As a result the particlesonce again become susceptible to agglomeration with themselves and otherparticles, and are hence once again susceptible to re-deposition.

SUMMARY OF THE INVENTION

[0013] The present invention provides an aqueous composition of matterwhich comprises a copolymer component comprising a water soluble anionicform of styrene/methacrylic acid copolymer and a metal component. Thecopolymer preferably has a styrene content in the range of about 10.0%to about 45.0% by weight based upon its total weight, and has amolecular weight in the range of about 1,000 to about 100,000. The metalcomponent comprises an aqueous solution containing at least onemultivalent cation selected from the group consisting of: calcium,magnesium, strontium, barium, nickel, copper, tin, cobalt, iron, zinc,or mixtures thereof. The ratio of the copolymer component to the metalcomponent is in the range of between 1:4 to 1:500 on a weight basis.

[0014] In order to use a composition according to the invention, oneintroduces an effective deposition inhibiting amount of said aqueouscomposition into a process stream in which pitch, resin, lignin, andother residues exist or are liberated. The concentration of thecopolymer component in an aqueous composition according to the inventionin the process stream is in the range of between about 0.5 parts permillion to 500 parts per million by weight based upon the weight of theprocess stream. The metal component content in a composition accordingto the invention is calculated based upon the amount of copolymerpresent. One preferred form of the invention employs a copolymercomponent concentration of between about 10 ppm to 50 ppm based upon theamount (weight basis) of the process stream treated and the metalcomponent is calcium ion, present at between about 100 ppm to 500 ppm,also based upon the amount (weight basis) of the process stream treated.

DETAILED DESCRIPTION

[0015] The present invention provides a composition of matter whichcomprises at least one styrene/methacrylic acid copolymer in combinationwith a multi-valent metal cation, which compositions according to theinvention are preferably aqueous solutions comprising these components.To provide a composition according to the invention, one first providesthe copolymer component as an aqueous solution of its alkali metal salt.Suitable metals include lithium, sodium, potassium, rubidium, etc. Apreferred ratio of styrene to methacrylic acid in the copolymer is 40:60on a weight basis; however, copolymers having any content of styrene inthe range of 10.0% to 45.0%, by weight based upon the total weight ofthe styrene/methacrylic acid polymer, including every hundredthpercentage therebetween, are suitable for use in the present invention.

Styrene/Methacrylic Acid Copolymer and Water Soluble Salt Thereof

[0016] The preparation of styrene/methacrylic acid copolymers isstraightforward and is known in the art. One method for preparing suchcopolymers useful in the present invention involves fitting a 3-neckedIL flange flask with a mechanical stirrer, heating mantle, thermometer,reflux condenser, addition inlet, and provision for maintaining an inertatmosphere within the reaction vessel, such as a nitrogen inlet. Theflask is charged with three hundred thirty six (336) grams ofisopropanol and one hundred twelve (112) grams of water. Heating iscommenced under stirring and slow nitrogen sweep until a gentle refluxis achieved, at about 80 deg. Centigrade. A first stream comprisingeighty (80) milliliters of a 5% aqueous sodium persulphate solution wasslowly added to the contents of the refluxing contents of the flasksimultaneously with a second stream comprising a liquid mixture of 70.4grams of styrene and 105.4 grams of methacrylic acid, over the course ofabout 2 hours. Following the addition, the temperature was maintained atreflux for an additional 2 hours to ensure complete reaction. Then, anadditional ten (10) milliliters of 22% sodium persulphate was added, andthe temperature maintained at reflux for one additional hour to providea styrene/methacrylic acid copolymer.

[0017] To prepare the sodium salt of the aforesaid polymer, the flaskfrom the above was set up for distillation by affixing a head andcondenser thereto. The flask is heated until the azeotrope ofisopropanol and water begins to distill, and then two hundred thirteen(213) grams of a 23% (wt.) aqueous solution of sodium hydroxide isslowly added to the flask during the distillation at a rate which isapproximately equal to the rate at which the azeotrope is beingdistilled. The temperature of the contents of the flask are monitored,and when the temperature reaches 100-105 deg., the flask is allowed tocool to 50 degrees centigrade and the pH is adjusted to a level betweenabout 8 and 10 using aqueous NaOH, and to a total solids content ofbetween about 30 and 35% (wt.) as determined by evaporation of all ofthe water from a sample of known weight and dividing the weight of thesolids remaining by the total initial weight and converting to apercentage by multiplication by 100.

[0018] The above procedure affords an aqueous solution comprising thesodium salt of styrene/methacrylic acid copolymer, to which may be addeda multivalent metal ion in order to afford a composition according tothe invention which is useful as an anti-coagulation additive for pitchand resinous materials in paper mills and other systems.

[0019] Although the styrene/methacrylic acid ratio in the abovepreparatory method is about 40:60, copolymers of styrene and methacrylicacid having other ratios are also useful herein as the copolymercomponent from which an anti-coagulant additive may be formed. Thecopolymers having any content of styrene in the range of 10.0% to 45.0%,by weight based upon the total weight of the styrene/methacrylic acidpolymer, including every hundredth percentage therebetween, are suitablefor use in the present invention. These polymers having varied amountsof styrene and methacrylic acid are made by altering the relativeamounts of each of the components in the second stream referred to inthe preparatory method above. For example, when a copolymer having astyrene to methacrylic acid ratio of 30:70 is desired, the second streamcomprises 52.70 grams of styrene and 123.06 grams of methacrylic acid.When a copolymer having a styrene to methacrylic acid ratio of 20:80 isdesired, the second stream comprises 35.15 grams of styrene and 140.61grams of methacrylic acid.

[0020] Although the water-soluble salt of the copolymer whosepreparation is described above as being the sodium salt as formed by theaddition of aqueous sodium hydroxide in the final step in which thealcohol is removed by distillation, other basic substances which producea water-soluble polymer are suitable as employment as neutralizingagents herein. Such basic substances include without limitation alkalineaqueous solutions or suspensions of other soluble metal cations, metaloxides, carbonates, etc., including without limitation, basic carbonatesof any of the alkali metals or monovalent iron, the basic oxides of anyof the alkali metals or monovalent iron, ammonia, or alkyl aminesincluding primary, secondary and tertiary amines provided that asolution of the copolymer results after the admixture and heating. Incases where suspensions of oxides are used, a longer heating time may benecessary to effectuate solution, depending upon the particle size ofthe basic substance.

[0021] The final polymers produced according to a procedure such as thatdescribed above may have molecular weights of any molecular weight valuein the range of about 1,000 to about 100,000, with molecular weightshaving any value in the range of 1,500 to 50,000 being preferred, withmolecular weights having any value in the range of about 2,000 to about30,000 being most preferred.

The Multivalent Metal Component

[0022] Compositions prepared in accordance with and useful in thepreferred form of the present invention are prepared from combining asolution of a copolymer component with a solution or suspension of ametal cation component. The multivalent metal component (or “metalcation” component) useful for admixture with the soluble copolymercomponent in accordance with the present invention may contain any metalcation which reduces the contact angle of the copolymer sufficiently tomodify the surface of pitch, stickies, or the like from hydrophobic tohydrophilic. It is preferred that a multivalent cation used in thepresent invention is capable of existing and is present in a di-valentform. Thus, any metal for which stable divalent compounds are known toexist is suitable for use in the present invention. Such metals include,without limitation, magnesium, calcium, strontium, barium, nickel,copper, tin, cobalt, iron, and zinc. It is preferred that themultivalent metal is a divalent metal. It is more preferred that themultivalent metal is a metal selected from the group consisting of thealkaline earth metals. It is most preferred that the multivalent metalis selected from the group consisting of calcium and magnesium.

The Anti-Coagulant Compositions

[0023] Although a solution of a multivalent metal ion and a solution ofa soluble copolymer of styrene and methacrylic acid may both be addedseparately to an aqueous system, it is preferred that these materials bemixed with one another prior to their being added to the system. This isbecause it is believed that the two species interact with one another toform an adduct or complex which possesses anti-coagulant properties forresin, pitch, lignin, and other bodies present in these aqueous systems.The present invention is concerned with preventing the deposition ofparticles derived from lignin, pitch, resin, and the like onto variousarticles and pieces of process equipment and these terms are intendedherein to refer to any material which can be considered to form a stickyresidue including without limitation: natural resins (fatty and resinacids, fatty esters, insoluble salts, sterols, etc.); defoamers (oil,EBS, silicate, silicone oils, ethoxylates); sizing agents (rosin size,ASA, AKD, hydrolysis products, insoluble salts); coating binders (PVAC,SBR); Waxes, Inks, Hot melt glues (EVA, PVAC, amorphous polyolefins);contact adhesives (SBR, vinyl acrylates, polyisoprene, and the like).From a physical standpoint, such deposits typically form frommicroscopic particles of materials having adhesive outer surfaces in thestock which accumulate on papermaking or pulping equipment. Suchdeposits are often found on stock chest walls, paper machine foils, Uhleboxes, paper machine wires, wet press felts, dryer felts, dryer cans,and calendar stacks. Such particles formed from resins, pitch, ligninsand the like are usually particles of visible or nearly visible size.

[0024] To form a composition according to a preferred form of theinvention, one begins with a first solution that contains a watersoluble salt or solution of the copolymer, and a second solution thatcontains a soluble aqueous solution of the divalent metal selected. Avessel containing either of the solutions is caused to undergoagitation, and a stream of the second solution is slowly added to thefirst. Upon mixing of the two solutions, a clear solution is formed. Itis this final clear solution that results from admixture of the solublecopolymer solution with a multivalent metal ion that is useful as ananti-coagulant in accordance with a preferred form of the presentinvention. Such a final solution containing an anti-coagulant may besimply added to the pulp mill's water system at any location which isupstream from the point where the pitch, resin, or lignin-derivedmaterial first comes into contact with calcium ions (typically from anoutside water source used as rinse or process water) because calciumions can react with pitch, resin, or lignin-derived material to formmicroscopic sized particulate precipitates, which particulateprecipitates are capable of agglomerating with one another to formundesirable films and gummy precipitates.

[0025] As mentioned, the compositions of the present invention areeffective at inhibiting the deposition of organic contaminants in allpapermaking systems regardless of the type of process employed includingwithout limitation Krafft, acid sulfite, mechanical pulp and recycledfiber systems. Deposition in the brown stock washer, screen room, andDecker system in Krafft papermaking processes can be inhibited accordingto the teachings of the invention. The present compositions can beutilized to inhibit deposition on all surfaces of any papermaking systemfrom the pulp mill to the reel of the paper machine, including thoseprocess contents having any pH in the range of about 3 to about 11, andunder a variety of other system conditions including temperatures, ionicstrengths, solids content, etc. More specifically, thestyrene/methacrylic acid compositions effectively decrease thedeposition not only on metal surfaces but also plastic and syntheticsurfaces such as machine wires, felts, foils, Uhle boxes, rolls andheadbox components. Further, the compositions of the present inventionmay be used with other pulp and papermaking additives including withoutlimitation starches, whiteners such as titanium dioxide, defoamers, wetstrength resins, sizing aids, and any other material known to thoseskilled in the art as being useful as a functional additive in apapermaking system.

[0026] The compositions of the present invention can be added to thepaper-making system at any stage. They may be added directly to the pulpfurnish or indirectly to the furnish through the headbox. In anotherform of the invention, an anti-coagulant composition prepared inaccordance with the teachings herein may be sprayed directly onto piecesof equipment which are desired to be protected from the gummyprecipitates or films. Also, a composition according to the inventionmay be sprayed onto areas upon which are already deposited gummyresidues from pitch, resin, lignin, etc. Such areas may include withoutlimitation wires, press felts, press rolls and other deposition-pronesurfaces. When added by spraying techniques, the composition ispreferably diluted with water to a satisfactory inhibitor concentration.Thus, a composition according to the invention may be added to any pointin a pulp and papermaking system. Spraying may be conducted using aspray bar, atomizer, or other means known by those skilled in the art ofproviding a spray to a surface.

[0027] The compositions of the present invention can be added to thepapermaking system neat, as a powder, slurry or in solution; thepreferred primary solvent including without limitation, water. Thecompositions may be added specifically and only to a furnish identifiedas contaminated or may be added to blended pulps. The compositions maybe added to the stock at any point prior to the manifestation of thedeposition problem and at more than one site when more than onedeposition site occurs. Combinations of the above additive methods mayalso be employed by feeding the pulp millstock, feeding to the papermachine furnish, and spraying on the wire and the felt simultaneously.

[0028] It is preferred that the weight ratio of styrene/methacryliccopolymer to multivalent cation in the complex formed according to theinvention ranges from about 1:4 to about 1:500. More preferably, thisratio is in the range of between about 1:10 to about 1:400. It is mostpreferred that the weight ratio of styrene/methacrylic copolymer tomultivalent cation in the complex formed according to the inventionranges from about 1:15 to about 1:300.

[0029] In use in an aqueous system in which there exist chemical speciesderived from resins, lignins, pitch, etc. which are capable of formingmicroscopic particles in the presence of calcium, which particles have apropensity to agglomerate to form an insoluble fouling, gummy film onplant equipment and the like, to which a composition according to theinvention is to be added, the total concentration of thestyrene/methacrylic acid copolymer present which is effective forpreventing agglomeration of gummy residues on plant equipment and thelike is between about 0.5 parts per million to 500 parts per million ofstyrene/methacrylic acid copolymer, based upon the weight of the pulp orsolution to which a composition according to the invention is added. Itis more preferred that this concentration is in the range of about 2.0parts per million to 100 parts per million of styrene/methacrylic acidcopolymer, based upon the weight of the pulp or solution. It is mostpreferred that the total concentration of copolymer present is in therange of between 5 and 80 parts per million based upon the weight of thepulp or solution to which it is added.

[0030] For purposes of the present invention, the term “an effectivedeposition inhibiting amount” is defined as that amount which issufficient to inhibit deposition of residues derived from pitch, resin,lignin, and the like in pulp and papermaking systems. The effectiveamount to be added to the papermaking system depends on a number ofvariables including the pH of the system, hardness of the water,temperature of the water, additional additives, and the organiccontaminant type and content of the pulp. Generally, from about 0.5parts to about 150 parts of the inventive composition per million partsof pulp is added to the papermaking system. Preferably, from about 2parts to about 100 parts of the inventive composition are added permillion parts of pulp in the system.

[0031] The data set forth below were developed to evaluate test resultsobtained through use of the present invention. However, it quicklybecame evident that a synergistic result was discovered with respect tothe contact angle measurements and the amount of calcium ion present.The following data are included as being illustrative of the presentinvention and should not be construed as being delimitive thereof in anyway.

Surface Tension and Contact Angle Measurements

[0032] Contact angle measurements provide direct information about thehydrophobicity of a surface which is coated with a sticky substance,such as an agglomerated residue derived from a pitch, lignin, resin,etc. These measurements are thus capable of providing information aboutthe change in the hydrophobicity of a surface as surface-activematerials are adsorbed and/or de-sorbed at the surface. A lower contactangle indicates that the surface is less susceptible to deposition ofsuch gummy residues. A zero contact angle is most preferred. Surfacetension provides information about the surface activity of thesurfactants. A lower surface tension indicates that the surfactant canemulsify and therefore stabilize the pitch dispersion more effectively.A stable dispersion will, in turn, minimize or prevent deposition.

[0033] A well-known Wilhelmy-type technique was used to obtain surfacetensions and receding contact angles of a solid immersed in thesolutions containing different treatments. The Kruss K-12 Tensiometerwas used. The experiment was performed at room temperature (23.degree.C.). A clean platinum plate with exactly known geometry is brought incontact with liquid and the force acting on the plate is measured via amicrobalance. The surface tension of the liquid is calculated from themeasured force:

λ=P/(L×COS θ)

[0034] in which λ=surface tension; P=measured (Wilhelmy) force; andL=wetted length. In this equation, θ is the contact angle between thetangent at the wetting line and the plate surface. For the determinationof the surface tension, the roughened and cleaned platinum plate is usedand its contact angle is zero.

[0035] A packaging tape made from a styrenebutadiene rubber and vinylicesters and a polyester film such as MYLAR® (trademark of E. I. DuPont deNemours), were used as a solid substrate for contact angle measurements.For the testing, a clean solid substrate was clamped on a film stage,then placed in a glass test cell. The test solution was added to thecell and the whole test cell was placed inside the chamber of agoniometer. The substrate was in contact with the solution for 30minutes and after which an air bubble was positioned on the underside ofthe substrate with an inverted tip. Contact angle provides informationabout the hydrophobicity of a simulated surface comprising a pitch,resin, or lignin and the change in the hydrophobicity as surface-activematerials are adsorbed and/or de-sorbed at the surface. A lower contactangle is indicative of the surface being less susceptible to stickiesand/or pitch deposition. Surface tension provides information about thesurface activity of the surfactants. A lower surface tension indicatesthat the surfactant is likely to adsorb at the contaminant's surface andthereby, stabilizing the pitch dispersion more effectively. A stabledispersion will minimize or prevent deposition. The results of thistesting are reported in Table I The following abbreviations are used inthe examples which follow: STYMMA 1=styrene methacrylic copolymer (30 wt% styrene/70 wt % methacrylic acid); STYMMA 2=styrene methacryliccopolymer (10 wt % styrene/90 wt % methacrylic acid); STYMMA 3=styrenemethacrylic copolymer (40 wt % styrene/60 wt % methacrylic acid); STYMAA4=styrene methacrylic copolymer (50 wt % styrene/50 wt % methacrylicacid); STYMMA 5=styrene methacrylic copolymer (40 wt % styrene/60 wt %methacrylic acid but higher molecular weight than STYMMA 3);PVA=polyvinyl alcohol (88% hydrolysis); and DI H₂O=de-ionized water.TABLE I Surface Tension and Contact Angle Measurements at 23° C. ofsolutions having varied copolymer concentrations and calcium content inthe complex. Surf. ID copolymer Ca Tension Contact Angle No. Substancelevel ppm ppm (dyne/cm) (degrees) 1 DI H₂O 0 0 72.8 63.2 (MYLAR ®) 70.9(Tape) 2 DI H₂O + 0 50 72.8 63.2 (MYLAR ®) Ca 70.9 (Tape) 3 STYMMA 1 1 0— 70.4 (Tape) 4 STYMMA 1 50 0 72.5 62.4 (MYLAR ®) 5 STYMMA 1 1000 0 —56.8 (MYLAR ®) 6 STYMMA 1 0.5 50 — 41.2 (Tape) 7 STYMMA 1 1 50 — 32.4(Tape) 8 STYMMA 1 10 50 54.6 21.6 (MYLAR ®) 9 STYMMA 1 50 50 50.23 13.1(MYLAR ®) 10 STYMMA 3 1 50 — 26.0 (Tape) 11 PVA 1 0 — 51.9 (Tape) 12 PVA3 0 — 45.9 (Tape)

[0036] The results presented in Table I demonstrate that the STYMMApolymers operate synergistically with calcium towards minimization ofthe contact angle. Contact angle measurements are shown in example 2, at50 ppm calcium and in the absence of copolymer for both substrates ofTape and MYLAR®. Looking at examples 3-5 shows the contact anglemeasurements for varying levels of copolymer but in the absence ofcalcium, and from the examples 2-5 it is clear that for both cases wherecopolymer is present in the absence of calcium and where calcium ispresent in the absence of copolymer, the magnitude of the contact anglemeasured is about the same in both cases, in the range of about 55-70degrees. However, as is evident from the examples 6-10, when calcium andcopolymer are both present, the contact angle drops dramatically, inevidence of the heretofore unknown synergy between styrene/methacrylicacid copolymers and calcium ion towards altering the hydrophobicity of asimulated surface comprising a pitch, resin, or lignin and the change inthe hydrophobicity as surface-active materials are adsorbed and/orde-sorbed at the surface. The most dramatic effect is evident fromcomparing examples 9 and 4, which shows the dramatic effect of thepresence of calcium on the decrease in the surface tension and contactangle.

Standard Tape Detackification Test

[0037] This test method measures the effect of chemical additives oncontact adhesion. An adhesive tape (2″×4″) and a polyester coupon(2″×4″) were treated with the test solution (600 gram). The solutioncontained in a 600 mL beaker is placed in a water bath with agitationand heated to the desired temperature. After 30 minutes of immersion,the tape and coupon are removed from the solution and pressed to 10,000lb force for 1 minute and then the peel force is then measured. Areduction of peel force indicates the level of detackification of theadhesive surface. The more the adhesive surface is detackified, the lessthe deposition potential of particulate residues derived from pitch,lignin, resin, etc. would be. The % control or detackification iscalculated by the following equation:

% detackification=[(untreated force)−(treated force)]×100/untreatedforce

[0038] Results of this testing are set for the in Table II below: TABLEII Standard Tape Detackification Test Peel % Sample Dosage Ca Temp.Force detacki- No. Substance (ppm) (ppm) ° C. (lbf) fication 1 DI H₂O 050 5.13 0 2 STYMAA 1 0.15 0 50 4.50 2.2 3 STYMAA 1 0.15 5 50 4.00 13.0 4STYMAA 1 0.15 10 50 1.07 76.7 5 STYMAA 1 0.15 30 50 0.59 87.2 6 STYMAA 10.15 50 50 0.28 94.5 7 STYMMA 1 0.15 100 50 0.20 95.7 8 STYMMA 1 0.15500 50 0.31 93.3 9 STYMAA 1 0.10 100 50 0.93 79.8 10 STYMAA 1 0.25 10050 0.03 99.3 11 DI H₂O 0 0 25 6.1 0 12 STYMAA 1 0.25 0 25 6.02 0 13STYMAA 1 0.25 10 25 3.40 33.7 14 STYMAA 1 0.25 30 25 2.00 61.0 15 STYMAA1 0.25 50 25 1.77 65.5 16 STYMAA 1 0.25 100 25 0.68 86.7 17 STYMAA 10.25 200 25 0.52 89.9 18 STYMAA 1 0.25 500 25 0.36 93.0 19 PVA 1 25 0.6387.7 20 STYMAA 3 0.15 50 50 0.34 93.4 21 STYMAA 5 0.15 50 50 1.58 69.222 STYMAA 4 0.15 50 50 3.57 43.7 23 STYMAA 2 0.15 50 50 1.56 69.6

[0039] These results confirm the results set forth in Table I that theefficacy of styrene methacrylic acid copolymers towards inhibitingdeposition of the residues addressed herein is significantly increasedwhen it is used together with multivalent metallic species such ascalcium ions. From In examples 2-8 it is clear that increasing thecalcium increases the detackification values. Increased detackificationoccurs upon increasing the calcium concentration to about 50 ppm, afterwhich the performance levels are seen to level off Examples 11-18evidence the same performance qualities of the compositions, except atlower temperature, thus evidencing the temperature-independence of thegeneral effect discovered. In addition, there seems to be an optimumstyrene content as evidenced by examples 20-23, which is about 15% toabout 40%. Of the styrene methacrylic copolymers tested, STYMAA 1 andSTYMMA 3 exhibited the best performance as reflected by their ultra-lowpeel force. These results are in agreement with those obtained fromsurface tension and contact angle measurements. Thus these are preferredpolymer compositions according to the invention. Unless noted otherwise,all molecular weights specified in this specification and the claimsappended hereto in are on a weight-average molecular weight basis.

[0040] A composition according to one form of the present invention doesnot contain any pitch, stickies, or other materials known to thoseskilled in the papermaking art to cause fouling on papermakingequipment. This is because a composition according to the presentinvention is intended to be added to a papermill furnish or other fiberrefining operation in which stickies, pitch, and other foulingsubstances known to those in fiber processing arts are present, in orderto lessen their detrimental effect on the associated equipment.

[0041] Consideration must be given to the fact that although thisinvention has been described and disclosed in relation to certainpreferred embodiments, obvious equivalent modifications and alterationsthereof will become apparent to one of ordinary skill in this art uponreading and understanding this specification and the claims appendedhereto. Accordingly, the presently disclosed invention is intended tocover all such modifications and alterations, and is limited only by thescope of the claims which follow.

We claim: 1) An aqueous composition of matter which consists essentiallyof: a) water; and b) the complex formed between: i) a copolymercomponent comprising a water soluble anionic form of styrene/methacrylicacid copolymer in which the copolymer has a styrene content in the rangeof 10.0% to 45.0% by weight based upon the total weight of thestyrene/methacrylic acid copolymer, including every hundredth percentagetherebetween, and wherein said copolymer component has a molecularweight in the range of 2,000 to 30,000 including every molecular weighttherebetween; and ii) a metal component comprising an aqueous solutioncontaining at least one multivalent cation selected from the groupconsisting of: calcium, magnesium, strontium, barium, nickel, copper,tin, cobalt, iron, zinc, or mixtures thereof, wherein the ratio of thecopolymer component to the metal component is in the range of between1:4 to 1:500 on a weight basis. 2) A composition according to claim 1wherein the ratio of the copolymer component to the metal component isin the range of between 1:10 to 1:400 on a weight basis. 3) Acomposition according to claim 1 wherein the ratio of the copolymercomponent to the metal component is in the range of between 1:15 to1:300 on a weight basis. 4) A composition according to claim 1 whereinsaid copolymer component has a styrene content in the range of 15.0% to38.0% by weight based upon the total weight of the styrene/methacrylicacid polymer, including every hundredth percentage therebetween. 5) Acomposition according to claim 1 wherein said copolymer component has amolecular weight in the range of 5,000 to 25,000 including everymolecular weight therebetween. 6) An aqueous composition of matter whichconsists essentially of: a) water; and b) the complex formed between: i)a copolymer component comprising a water soluble anionic form ofstyrene/methacrylic acid copolymer in which the copolymer has amolecular weight in the range of 2,000 to 30,000 including everymolecular weight therebetween; and ii) a metal component comprising anaqueous solution containing at least one multivalent cation selectedfrom the group consisting of calcium, magnesium, strontium, barium,nickel, copper, tin, cobalt, iron, zinc or mixtures thereof, wherein theratio of the copolymer component to the metal component is in the rangeof between 1:4 to 1:500 on a weight basis. 7) A composition according toclaim 6 wherein the ratio of the copolymer component to the metalcomponent is in the range of between 1:10 to 1:400 on a weight basis. 8)A composition according to claim 6 wherein the ratio of the copolymercomponent to the metal component is in the range of between 1:15 to1:300 on a weight basis. 9) A composition according to claim 6 whereinthe molecular weight of the copolymer is in the range of 5,000 to24,000, including every molecular weight therebetween. 10) A compositionaccording to claim 6 wherein the molecular weight of the copolymer is inthe range of 9,000 to 18,000, including every molecular weighttherebetween. 11) A composition according to claim 6 wherein themolecular weight of the copolymer is in the range of 11,000 to 15,000,including every molecular weight therebetween. 12) An aqueouscomposition of matter which consists essentially of: a) water; and b)the complex formed between i) a copolymer component comprising a watersoluble form anionic of styrene/methacrylic acid copolymer in which thecopolymer has a styrene content in the range of 10.0% to 45.0% by weightbased upon the total weight of the styrene/methacrylic acid copolymer,including every hundredth percentage therebetween; and ii) a metalcomponent comprising an aqueous solution containing at least onemultivalent cation selected from the group consisting of calcium,magnesium, strontium, barium, nickel, copper, tin, cobalt, iron, zinc,or mixtures thereof, wherein the ratio of the copolymer component to themetal component is in the range of between 1:4 to 1:500 on a weightbasis. 13) A composition according to claim 12 in which the styrenecontent of the copolymer is in the range of between about 15.0% and35.0%, by weight based upon the total weight of the styrene/methacrylicacid copolymer, including every hundredth percentage therebetween. 14) Acomposition according to claim 12 in which the styrene content of thecopolymer is in the range of between about 18.0% and 30.0%, by weightbased upon the total weight of the styrene/methacrylic acid copolymer,including every hundredth percentage therebetween. 15) A compositionaccording to claim 12 in which the styrene content of the copolymer isin the range of between about 21.0% and 27.0%, by weight based upon thetotal weight of the styrene/methacrylic acid copolymer, including everyhundredth percentage therebetween. 16) A process for preventingdeposition of pitch, resin, stickies, lignin, and other residues onprocessing equipment in processes in that such species are present whichcomprises the steps of: a) providing an aqueous composition of matterwhich comprises: i) a copolymer component comprising a water solubleanionic form of styrene/methacrylic acid copolymer; and ii) a metalcomponent comprising an aqueous solution containing at least onemultivalent cation selected from the group consisting of calcium,magnesium, strontium, barium, nickel, copper, tin, cobalt, iron, zinc,or mixtures thereof, and b) introducing an effective depositioninhibiting amount of said aqueous composition into a process stream inwhich pitch, resin, lignin, and other residues are liberated, whereinthe concentration of the copolymer component of said aqueous compositionin said process stream is in the range of between 0.5 parts per millionto 500 parts per million by weight based upon the weight of said processstream. 17) A process according to claim 16 wherein the concentration ofthe copolymer component of said aqueous composition in said processstream is in the range of between 2.0 parts per million to 150 parts permillion by weight based upon the weight of the process stream 18) Aprocess as in claim 16 wherein the metal component is present in saidprocess stream in any amount between 4 times the amount of the copolymercomponent and 500 times the amount of the copolymer component. 19) Aprocess as in claim 17 wherein the metal component is present in saidprocess stream in any amount between 4 times the amount of the copolymercomponent and 500 times the amount of the copolymer component. 20) Aprocess according to claim 16 wherein said multivalent cation isselected from the group consisting of: calcium and magnesium; andwherein the molecular weight of the copolymer is in the range of 2,000to 30,000 including every molecular weight therebetween